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Os Palatin ou du Palais, is a small bone, of an irregular shape, situate at the posterior part of the nasal fossae and palate. It seems formed by the union of two bony plates joined at right angles to each other; so that one is inferior and horizontal; - the other, superior and vertical. The horizontal or palatine portion, Arch of the palate, is quadrilateral. Its upper surface forms part of the nasal fossae; the lower forms part of the palatine arch, and contains the inferior orifice of the posterior palatine canal. Its anterior edge is articulated with the palatine process of the superior maxillary bone; the posterior is free and sharp. It gives attachment to the velum palati, and presents an eminence, which, when joined with one on the opposite side, forms the posterior nasal spine. Its inner edge is articulated with the corresponding bone; its outer is confounded with the vertical portion. The vertical or ascending portion has the form of a long square. The inner surface forms part of the outer paries of the nasal fossae. Its outer surface is unequal, and is articulated with the superior maxillary bone; behind, it presents a vertical groove, which forms part of the posterior palatine canal; and, above, a small free surface, which looks into the zygomatic fossa. Its anterior edge is united with the superior maxillary bone; the posterior is unequal, and rests on the internal ala of the pterygoid process. The angle, which it forms by uniting with the posterior edge of the horizontal portion, presents a very prominent pyramidal eminence, called the tuberosity of the palate bane. Its upper margin is surmounted by two eminences ;-the one, anterior, called the orbitar process; - the other posterior, the sphenoid process. These two processes are separated by an almost circular notch, which the sphenoid bone forms into a foramen, called the sphenopalatine. This bone appears to be developed from a single point of ossification. It is articulated with the sphenoid, ethmoid, the cornna sphenoidalia, superior maxillary bone, the inferior spongy bone, the vomer, and its fellow.

See palatal bone